Brake



Jan. 19, E H BERNQ Ef'AL BRAKE Filed Oct. 7, 1949 2 Sheets-Sheet 1 Cam-m P RES SURE or Snot as 44 INVENTOR. 3 96 21 EDWARD H. BERNO 52 BY 'Eowm J. BALLUFF Jan. 19, 1954 BERNO ETAL 2,666,504

BRAKE Filed Oct. 7, 1949 2 sheets sheet 2 nos as 98 I04 36 II. E=E Q as i ///////A I50 A 54 VIII/III! IE1 13:.1. III

IN VEN TOR.

EDWARD H. BERNO By Eowm J. BALLUFFH Patented Jan. 19, 1954 UNITEDSTA'TES PATENT OFFICE I BRAKE Edward H. Berno, Plymouth, and Edwin J. Balluiif, Farmington, Mich.

Application October 7, 1949, Serial No. 120,138

Claims.

This invention relates to brakes and has par ticular reference to wheel brake structure.

A principal object of the invention is to provide a new and improvedbrake- I .6

Another object of the invention is to provide a new and improved brake structure which is more eificient in performance and less expensive-to manufacture than brakesnow available.

Other and further objects of the invention will be apparent from the following description and claims and may be understood by reference to the accompanying: drawings, of which there are two sheets, which by way of illustration show a .preferred embodiment of the invention! and what we now consider to be the best mode in which we have contemplated-applying-the principles of our invention. Other embodiments of the invention may be usedwithout departing from the scope of the present invention as setforth. in the appended claims." I? Y r In the drawings: i w 1 Fig; 1 is an elevational view of thewheel brake structure with certain parts .shown in' section;

Fig. 2 is an enlarged fragmentary sectional view taken along theline 22 of Fig. 1, looking in the directionof the-arrows;

Fig. 3 is asection taken along the 1ine1ill-3- of Fig. 2, lool zing in' the direction of the arrows; Fig. 4v is. an enlarged fragmentary elevational view of the. articulated 'connection'between the shoes;

Fig. 5 isra sectiona-lcviewtalrenalongtheline l'oolsing ini the direction of the 55 io'f Fig.1,

arrows;

Fig. 6. is anxenlargecl fragmentaryfiectional view taken :along the .line, 6-6v of Fig.6 1 1 r Fig. 7 is an enlarged sectionalviewvtaken along the line 1-1 of Fig."1,.1ooking in the direction of the arrows;-"

Fig. 8"is an enlarged sectional view taken brake embodying the invention comprises in gen:

eral a drum 20, 211 anchor-pin-i22 'a secondary shoe 24 having lining iz s'shapd to conform thecurvature of thedrum, a primary shoe28' having lining 30 shaped to conform with the curvature of the drum, brake applying means comprising a hydraulic cylinder and piston unit 32, a brake shoe retracting spring 34, an anchor plate 36, and a dust shield 38.

The anchor plate 36 may comprise a heavy steel stamping or forging which is secured to the flange 42 of the axle housing with the dust shield 38 clamped therebetween by the bolts 42 which secure the anchor plate 36 to the flange 4D. The dust shield is arranged to close the open side of the drum'20. The anchor pin 22 is suitably secured in an opening inthe anchor plate 36 and projects laterally therefrom in op-.

posite directions, as clearly shown in Figs. 2 and One end 44 ofthe brake shoe 24 is provided with a hole or aperture 46 in which a bushing 48 is secured. The bushing has a hole 50 therethrough through which the anchor pin 22 extends, the size of the hole relative to the cross section of the pin 22 being such as to providea floating connection between the end 44 of .the shoe and the anchor pin 22 which providesfor pivotal movement of the shoe 24 about the anchor 'pin 22 and for floating movement of the shoe 24 with respect to the anchor pin 22 ,and toward and away from the drum 2!! so that the shoe and the lining 26 thereof are free to conform with the curvature of the drum 2!]. V a I Thebushing .48 has one side 52 of. the hole 50 formed with a reverse curveportion which engages the flat 54 on the side of the pin 22. r The flat 54 on the pin 22 lies in a plane which is approximately parallel to a line which extends between the center of rotation of the drum 2!! and the axis of the pin 22. The brake is shown in Figs. 1 and 2 in applied position during forward rotation of the drum 2!], and in this position the portion 52 seats on and reacts against the flat 54 on the pin 22. V p

The floating connection between the anchor pin 22 and the shoe 24 permits the shoe 24 to 46 float on the anchor pin 22 so that the lining 26 is free to conform with drum curvature and/or distortion during brake application.

While the cross section of the shoes 24 and 28 may be ofgthe conventional T shape, such shoes are non-rigidso as to permit deflection oithe. shoes during brake application in order that' 'they'may conform with the curvature of the drum 20.. V. v

Theflat 54 in effect forms a tangential slot in the pin 22. The bushing 48 at one side abuts the anchor plate 36. A lever is pivoted on the bushing 48 and disposed between the web of the shoe 24 and the anchor plate 36,. the lever 58 forming part of a means for mechanically actuating the shoes 24 and 28.

A hold down spring arrangement as illustrated in Fig. 6 is employed for holding the shoes 24 and 28 against the dust shield 38, and this comprises a spring 62am; a cotter pin 6i! which extends through oval holes 64 and 68 in the 'dust shield 38 and shoe 24 respectively. The coil spring 62 is assembled on the cotter pin and seated against the bent back ends 68 of the legs thereof. The head in of the pin 68 is then passed through the oval shaped holes 66' and'l54. There.- after the pin is turned ninety degrees" and seated in a cross slot in the dust shield 38 which prevents the pin 60 from turninglthe tension of the spring 62 holding the head Ill of the pin seated in the cross slot in the dust shield 38. The pin and. spring 62 hold the ed e of the back 12 of the shoes 24 and 28 against inwardly offset flats I4 on the shield 38.

The other end I6 of the shoe 2.4 is provided with a curved surface I8 upon which the curyed end 88 of the shoe 28 seats, this arrangement providing a pivotal mounting for the shoe 28 on the end I6 of the shoe 24. Referrin to Fig. 3, it will be observed that the articulated ends of the shoes 24 and. 28 are confined between an extension of the anchor plate 36 and. a fiat 82 formed on the dust shield 38. A spring 84 engaged at one end in a hole in the shoe 28 at its other end in a notch in the shQe 24 biases the surfaces I8 and 88 into pivotal relation.

' The hydraulic cylinder and piston unit 32 comprises a cylinder member 86, a piston merry ber 88 reciprocably arranged in the cylinder of the member 86, a cuprshaped member 92 pi resilient material, such as rubber, seated on the face of the piston 88, and a flexible boot 9'1 which extends between the piston 88 and the inner wall of the cylinder member 85 so as to form a dirt seal therebetween.

The cylinder member 86 is provided with topics 96 and 88which straddle theend .44 Of HE 10? 24' and the anchor plate 3! 5. Each of the forlgs is bifurcated, forming slots Illfi and H)? through which the anchor pin 22 extends, and fingers I04 which straddle the pin 22.

The pin 22 isprovide'dwith a portion of re: duced diameter 'which forms a shoulder Hit which seats against the anchor plate 36. A bushing I03 is secured on the reduced portion of the pin122 so that the slots I08 and I82 be: tween the fingers IQII may both be of the same site. The pin 22 iorms a pivotal mounting for the cylinder rnernber 86.

fThe piston 88 "is provided with a button Ht which isadapted to seat"against"a boss or pro! jectio nlI z on the end 446i the brake shoe 24. During braking upon forward "rotation of the drum,"and in which position the parts are shown in Figs. l and 2 the piston seatson' the end of the shoe 24 through the contact between the button III) and the projection H2. The rotai n of e d m c us s. the D ess shoes :4. an 28 to, tend to turnwith 'thedrum, thereby causing the'curved manners: the: shoe 24 to seat e ms the for 54 e W Pi 2- The introduction or hydraulic fluid into the cylinder from'theoonventional master cyl-Q. inder causes the piston I38 and the cylinder member 86 'to move apart. The cylinder member 58% is provided with a circular boss. us which sli the. (5311 ably receives a pin or link H8. The other end of the pin I I8 is bifurcated and engages the web I20 of the shoe 28 so as to react thereagainst upon actuation of the unit 32. A cap I22 is threaded on the threaded portion of the pin H8 and seats on the circular boss H6. Rotation of the cap I22 in one direction or the other will rieie r r t e pie ll? so a to ju the effective length of the .cslinder member at. The cap I22 is provided with a notched flange I24 which may be engaged by a suitable tool through an opening in the dust shield 38 for egljusting the same. Suitable means are provided to prevent accidental rotation of the cap 2; 0. 2 21 pin us.

The cylinder member 86 is provided with an integral boss 2 which extends through an open ing in the dust shield 38 and is provided with a threaded opening so that one end of a fluid pressure line I30 may be connected to the cylinder member 85 in order to supply p essure fluid to the cylinder 88 thereof when it is desired to apply the brakes. The boss I26 extends freely through the opening 12.8 in the dust shield .33 so as not to interfere with the pivotal and slidin movement of the cylinder member .86..

When fluid under pressure is introduced int thecylinder 90, the cylinder member 86 and piston member 88 will move away from eac otherythe piston member .88 reacting on the projection II2 of the shoe 24 and the cylinde member 86 reactin 9n the web at the fre end of the shoe 28. Application of sufficient pressure fluid to the cylinder 80 will overcome the force of the retracting spring 34 and enga the lining on .the shoes 24 and 28 with the drum 20. Rotation of the .drum in a forward direction willicause the portion .52 of the shoe to seat on the flat 54 and react thereagainst.

The shoe 28 not only is self-energizing, but also produces a servo effect on the shoe 24 since the shoe 28' is pivoted on the end ofthe shoe 24. The shoe 28 and the piston 88 will eflect the applicar tion of the. shoe 24 to the drum, although the anchor pin 22 will take the braking torque reaction of both shoes 24 and 28. When the prey sure fluid is released from the cylinder 90, the retracting spring 34 will retract the piston 38 and cylinder 88 relative to each other and also retract the shoes 24 and 28 from operative engagement with the drum 20.

Fig; '10 shows the relationship oi the cylinder member 86 and the shoe 24am! the bushing 48 relative to the anchor pin 22 during reverse brake ing'." [finder these conditions it will be observed that the slotted end of the forks 98 and 9B of the cylinder member seats against the anchor pin the piston 88 reacting on'the projection M2 to push the shoe 24 into engagement with the drum. The shoe 24 under these conditions willv act as the primary shoe and more the shoe. 28 in o 09: erative engagement with the drum which during reverse braking fun t It will be obse v he, ce ter 9i b0 3 2 Qii 5 9 i qF d proximately at the center of pressure of both hoe a in ca ed.

The cyl' 6. me

, erti e se forms. part of t c oses. ta m chanica y a itating the brake shoes and cooperates witli the lever 55 for thi- Pur o e- The ev 5.6. s provid d. with a bo h. is 35 able, win! a elder 5.3 on nde m m e sal y plying the bi s s; e oss. .31., he s hown n g'ss esei r 22 seaside lit n. 131s The lever 56 is pivoted on thebushing 46 sotl'iat when thelever 56 swings in a clockwise direction about its pivot it will react on the cylinder'IIS and thereby force the shoes 24 and 28 into braking engagement with the drum 20. The lever 53' is shown in its released position in Fig. 9.

A cable, I36 is provided with a ball I38 on one end thereof'which is arranged .in a socket I 40 formed on the lower end of the lever 56., The

socket I40 is formed by reversely bending the end is secured in an opening in the dust shield 38.

The cable I36 extends through the bushing I46 and is connected to a suitable lever whereby the lever 56 may be actuated to mechanically set the brakes. A boot I48 is connected at one end to the part of the bushing I46 disposed externally of the dust shield 38 and has a sliding fit on the cable I36 so as to prevent entrance of dirt into giant;

. x 6 plying part'reacting on said one end of said sec ondary shoeand the other pressure applying part thereof reacting on the other end of said primary shoe for forcing saidshoes into engagement with said drum upon actuation of said unit, said shoes and said hydraulic unit being supported solely by said anchor pin and being free to float thereon, said secondary shoe'reacting against said anchor pin for transmitting the braking torque of both the brake through the bushing I46 or the hole in the dust shield 38 in which the bushing I46 is arranged. The anchor plate 36 forms a surface on which the spring I42 is slidable.

The bushing I 46 is made in two equal parts and one end of the spring I42 seats thereagainst. The bushing is provided with an annular shoulder I50 which seats around the edge of the hole in the dust shield 38 through which the bushing I46 extends. In order to separate the bushing I46 from the dust shield 38, the boot I 48 is sep arated from the bushing I46 and the bushing is thereupon moved to the right along the cable and against the tension of the spring I42. After the bushing I46 has cleared the hole in the shield 38, the two parts thereof will separate radially.

If it is desired to disconnect the cable I36 from thelever 56, the ball I38 may be lifted out of the socket I40 by passing the cable I36 through the slot I45 which forms the entrance to the socket.

To assemble, the cable I36 and ball I38 may be assembled by reversing the operations just described. The spring I42 moves the lever 56 to its retracted or inoperative position as shown in Fig. 9 when the tension on the cable I36 is released.

While we have illustrated and described a pre ferred embodiment of our invention, it is understood that this is capable of modification and we therefore do not wish to be limited to the precise details set forth but desire to avail ourselves of such changes and alterations as fall within the purview of the following claims.

We claim:

1. Brake structure comprising a drum, an anchor plate, an anchor pin secured to said anchor plate and projecting from opposite sides thereof,

7 a secondary brake shoe shaped to conform with the curvature of said drum, one end of said secondary shoe having a floating connection with said anchor pin providing for floating movement of said secondary shoe relative to said anchor pin toward and away from said drum, a primary shoe having one end thereof reacting against the other end of said secondary shoe and shaped 'to conform with the curvature of said drum, a hydraulic piston and cylinder. unit having one pressure apshoes to said. anchor pin upon brake application in one direction of drum rotation, said one pressure'applying part of said unit having arms straddling said 'anchor plate and engageable with said anchor pin on opposite sides of said anchor plate for transmitting] thereto the braking torque of bothshoes upon brake application in the other direction of drum rotation.

"2.;Brake structure comprising a drum, an anchor pin, a secondary brake shoe shaped to conform with the curvatureof said drum, one end of said secondary shoe having a floating connection with said anchor pin providing for floating movement of said secondary shoe relative to said anchor pin and toward and away from said drum, 2. primary shoe having one end thereof provided with an articulated connected with the other end of said secondary shoe and shaped to conform with the curvature of said drum, a hydraulic piston and cylinder unit having one pressure applying part reacting on said one end of said secondary shoe and the other pressure applying part thereof reacting on the other end of said primary shoe for forcing said shoes into engagement with said drum, said shoes and said unit being supported solely by said anchor pin and being free to float thereon, said secondary shoe reacting 7 against said anchor pin for transmitting the braking torque of both shoes to said anchor pin upon brake application in one direction of drum rotation, said one pressure applying part of said unit being engageable with said anchor pin for transmitting thereto the braking torque of both shoes upon brake application in the other direction of drum rotation.

3. Brake structure comprising a rotatable drum, a fixed anchor member, a pair of articulated brake shoes shaped to conform with the curvature of the drum, an actuating unit having two relatively movable members reacting on the non-articulated ends of said shoes for forcing said shoes into engagement with said drum upon actuation of said unit, said shoes and said unit being supported solely by and having a floating connection with said anchor member whereby the braking torque of both shoes is transmitted to said anchor member upon actuation of said unit in both directions of drum rotation.

4. Brake structure comprising a rotatable drum, a fixed anchor member, a pair of articu lated brake shoes shaped to conform with the curvature of the drum, an actuating unit having two relatively movable members reacting on the non-articulated ends of said shoes for forcing said shoes into engagement with said drum upon actuation of said unit, one of said shoes having a floating connection with said anchor member and. reacting thereagainst for transmitting the braking torque of both shoes to said anchor member upon actuation of said unit in one direction of drum rotation, one of said members of said unit having a connection with said anchor member providing for relative movement therebetween, said one member reacting against said anchor member for transmitting thereto the braking 1 torque of Q hVShQQ D mactuation of said unit in the other direction ofdrum rotation.

5. Brake structure comprising a drum, an an chor pin, a secondary brake shoe shaped to con: form with the curvature of said drum, a floating connection between one end of said shoe and said anchor pin which provides for pivotal movement of said shoe about said anchor pin and for fioating movement of said shoe with respect to said anchor pin, and toward and away from said drum, so that the shoe is free to conform with the curvature of the drum, said pin having a fiat thereon and said shoe having a curved end engageable with said fiat and adapted to bear thereagainst during brake application in one direction, said flat being substantially parallel to a drum radius extending through the axis of said pin whereby said. end of said shoe moves substantially along said radius toward said drum upon brake application in said one direction of drum rotation, a

primary shoe having one end thereof pivoted to the other endof said secondary shoe and shaped to conform with the curvature of said drum, and means reacting on said one end of saidsecondary shoe and the other end of said primary shoe for forcing said shoes into engagement with said drum, said anchorpin being operable for taking all of the braking torque of both ShOes during brake application in both directions of drum rotation. V

EDWARD H. BERNO.

vEDWIN J. BALL-TIFF.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,209,772 Goepfrich et a1 July 30, 1940 2,256,728 Ambrose Dec .23, 19 i1 20 2,347,239 Berno Apr. 25, 1944 2,404,054 Goepfrich July 1c, 1946 

